Neonatal patients having one or two ventricle defects are dependent on the modified Blalock-Taussig shunt (mBTS) to establish proper systemic blood flow. While the procedure has saved many newborns with cyanotic heart defects, the obstruction of mBTS due to either thrombus and/or intimal build up has been problematic leading to high mortality and morbidity. In addition, the cost of care is among the most expensive for any surgical procedure. Shunt obstruction can lead to hypoxia and sudden death due to insufficient pulmonary circulation. Shunt occlusion can be sudden and without enough warning to prevent rapid deterioration of the patient?s condition. Alternatively, shunt obstruction can also occur gradually. But even in this case, the narrowing of the shunt lumen may result in similar adverse side effects. When emergency intervention is required, despite very aggressive resuscitation, it is frequently difficult to save infants with shunt obstruction. Recanalization can correct shunt obstruction. Imaging methods are inadequate to resolve obstruction within these 3-5 mm diameter shunts. Therefore, early detection of shunt obstruction is critical to avoid the need for emergency intervention and preventable loss of life. This proposal addresses the unmet clinical need for miniature sensors that can detect significant changes in blood flow through mBTS necessitating intervention. Developing flow sensors suitable for use with shunts poses several unique challenges but if successful, can reduce morbidity and mortality through timely, informed recanalization. The systematic approach involves first demonstrating proof-of-concept at the benchtop of non-contact flow sensing, followed by developing shunt sensor systems suitable for in vivo use, and then a final demonstration of wired sensors in a pig model. The expected outcome of this work is the demonstration of a non-contact flow sensor suitable for use with shunts to enable a sensor-shunt system as mBTS. The successful demonstration will pave the way for development of a wireless telemetry to enable a wireless mBTS for chronic animal studies. The non-contact sensing method also can be applied to other synthetic vascular grafts or drainage shunts. This proposal will establish proof-of-concept that is critical to achieve the long term goal of a wirelessly interrogated flow sensor system for periodic monitoring in a home care setting that enables early warning to drive intervention that saves lives.